1. Field of the Invention
The present invention relates to a wiring substrate on which a variety of electric and electronic components are mounted and a manufacturing method thereof.
2. Description of the Related Art
In the related art, there has been proposed a wiring substrate on which a variety of electric and electronic components are mounted, which has a connection terminal which is mounted and extended on a mounting surface of the substrate, and in which the connection terminal is connected to another wiring substrate, for example. For example, there have been proposed a structure in which a lead terminal is inserted and fixed in each through-hole of each substrate to connect the substrates (for example, refer to Patent Document 1), a structure in which in a circuit board which is integrally formed with a metal plate which is die-cut in a wiring pattern shape and a composite insulation material of high thermal conductivity in a state where at least a mounting portion of each electronic component is exposed, a part of the metal plate is used as an external connection terminal for connection with a different circuit board and the circuit board is easily position-controlled by a convex section disposed in the external connection terminal (for example, refer to Patent Document 2), and the like. In the circuit board in Patent Document 2, heat of mounted components is diffused by the metal plate and radiated by the composite insulation material.
Further, as shown in FIG. 48, a wiring substrate 4 is known in which a connector 2 is disposed on a mounting surface 1a of a substrate 1 and a connection terminal 3 of the connector 2 is upright installed on the mounting surface 1a of the substrate 1 for connection (for example, refer to Patent Document 3).    Patent Document 1: JP-A-6-275328    Patent Document 2: JP-A-10-303522    Patent Document 3: JP-A-2006-333583
As described above, as the wiring substrates are installed in parallel by connection through the connection terminals, it is possible to achieve high density mounting. However, with such a high density mounting, there is a problem in that insufficient heat radiation occurs since a heat radiation effect is achieved by only the substrates with the metal plate and the composite insulation material of high thermal conductivity.
Also recently, alongside the miniaturization of devices, there is demand for the miniaturization and thinning of a wiring substrate which is mounted in a device.
However, as in the wiring substrate disclosed in JP-A-6-275328 and JP-A-10-303522, if the connection terminal is installed on the mounting surface on which electric and electronic components are mounted, the size of the substrate has to be enlarged to mount necessary electric and electronic components thereon since the mounting surface of the substrate is occupied by the connection terminal. Further, in the wiring substrate disclosed in JP-A-2006-333583, since the connector is disposed on the mounting surface, the height is increased, and thus, it is difficult to achieve miniaturization of a substrate.